Year | Value | 2020 | 2.658 | 2019 | 2.538 | 2018 | 1.849 | 2017 | 2.261 | 2016 | 2.14 | 2015 | 1.972 | 2014 | 1.88 | 2013 | 1.585 | 2012 | 1.336 | 2011 | 1.407 | 2010 | 1.169 | 2009 | 1.152 | 2008 | 1.137 | 2007 | 1.122 | 2006 | 1.107 | 2005 | 1.067 | 2004 | 1.042 | 2003 | 0.944 | 2002 | 0.961 | 2001 | 0.904 | 2000 | 0.888 | 1995 | 0.85 | 1994 | 0.845 | 1993 | 0.844 | 1992 | 0.847 | 1991 | 0.835 | 1990 | 0.811 | 1989 | 0.858 | 1985 | 0.529 | 1981 | 0.552 | 1980 | 0.521 | 1975 | 0.235 | 1970 | 0.24 | 1965 | 0.255 | 1960 | 0.215 |
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